The wood has been widely used for generations as an optimum material for a building material and furniture from many advantages such as beauty of quality sense, easiness of working, or easiness of obtaining, and capable of recycling as resources.
And, case of intending to utilize the wood as described above, a matter which has been always a problem from years gone by to today is a problem of deciding how to handle a joining portion between members, in other words, a handling capable of bearing against a stress operating to the joining portions.
For instance of building material, nails or metal fittings have been used for the joining of column or girder in a small size house, and bolts, lug screws, drift pins have been used for the joining of trusses of a large size building.
However, in order to join the members without decreasing of strength by these methods, a number of joining materials or large sized metal fittings are required. As a result, problems are occurred that its cost is increased and beautiful appearance is decreased.
On the other hand, in accordance with an adhering method, the joining portion can be processed in small and beautiful, but this method is limited to a material that the member size is small as a furniture and a stress for transferring is not so big.
In a utilization of an adhering joining in a large wooden building, a great expectation has been had until now, but for a realization of this, an inducement of higher and newer adhesive agent in an adhering strength and a fireproof characteristic and a development of simple and reliable processing technique are indispensable.